Manual CAMT Processing does not consider EBICS User's Settings

[PatrickDEissler]

The function process_camt_document does not consider Split Batch Transactions from EBICS User.
Instead it takes the default: split_batch_transactions: bool = False,.

[barredterra]

It cannot consider these settings, because:

1. Manual CAMT upload is an alternative to EBICS download, they're not supposed to work together (except for debugging)
2. There is no link between Bank Account and EBICS User (an EBICS User can access many accounts, imported statements are mapped to a bank account via matching IBAN)

The best we can do is somehow add this setting to the file upload dialog.